The defendants — James Cromitie, David Williams, Onta Williams and Laguerre Payen — were charged with conspiracy to use weapons of mass destruction within the United States and conspiracy to acquire and use anti-aircraft missiles, the U.S. attorney's office said.

The defendants had allegedly planned to detonate a car with plastic explosives outside the Riverdale Temple, a Reform synagogue, and the Riverdale Jewish Center, an Orthodox synagogue, located near each other in the Bronx.

The men also allegedly sought to shoot military planes at the Air National Guard base at Stewart Airport in Newburgh with Stinger surface-to-air guided missiles.

The men, all of Newburgh, are due in federal court on Thursday in White Plains, N.Y.

Cromitie, David Williams and Onta Williams are native-born Americans; Payen was born in Haiti and is a Haitian citizen, according to authorities.

Three of the men converted to Islam, an official speaking on condition of anonymity told The Associated Press.

The arrests came following a nearly yearlong undercover operation that began in Newburgh, N.Y., about 70 miles north of New York City.

"They stated that they wanted to commit Jihad," Kelly said. "They were disturbed about what happened in Afghanistan and Pakistan, that Muslims were being killed."

Mayor Michael Bloomberg warned against stereotypes, stressing that Riverdale Temple is open to people of all faiths, including a Muslim girl who sometimes prays there. Bloomberg, Kelly and other city leaders met privately with congregants early Thursday to alleviate security concerns.

Asked why the suspects chose to target synagogues in the Bronx's Riverdale section, Kelly alluded to the proximity to highways, saying it could have been a fast getaway for the suspects.

The defendants planned to "destroy a synagogue and a Jewish community center (that is also a synagogue) with C-4 plastic explosives," acting U.S. Attorney Lev L. Dassin said.

Bloomberg said the alleged plot shows "that the homeland security threats against New York City are sadly all too real and underscores why we must remain vigilant in our efforts to prevent terrorism."

According to a criminal complaint, Cromitie began working with an FBI informant in June 2008 when he told the official that his parents had lived in Afghanistan and he was upset with the ongoing war there, including the deaths of many Muslims in Afghanistan and Pakistan by U.S. military forces.

Cromitie said he wanted to return to Afghanistan and told the informant about how he'd go to "paradise" if he died a martyr, the complaint said.

He also expressed an interest in doing "something to America," according to the complaint.

The following month, Cromitie and the informant discussed a Pakistan-based terror organization called Jaish-e-Mohammed that the informant claimed to be affiliated with.

In April 2009, Cromitie, David Williams, Onta Williams and Payen identified the synagogues they wanted to hit and began conducting surveillance of them as well as of the Air National Guard Base where they intended to strike military planes with Stinger missiles.

The informant supplied them with a missile he said he'd obtained from Jaish-e-Mohammed, but instead, it was an FBI-made device that wasn't capable of being fired, according to the complaint.

Cromitie, David Williams, Onta Williams and Payen are each charged with one count of conspiracy to use weapons of mass destruction within the U.S., which carries a maximum penalty of life in prison, and one count of conspiracy to acquire and use anti-aircraft missiles, which carries a maximum penalty of life in prison and a mandatory minimum of 25 years in prison.

Sen. John McCain, R-Ariz., told FOX News that former President Bush and the Department of Homeland Security should be credited for keeping the country safe following the Sept. 11 attacks.

"Maybe the Bush administration might deserve a little credit for the fact that there's not been another attack on the United States of America since 9/11," McCain told FOX News.

Sen. Charles Schumer, D-N.Y., said if there can be any good news out of this case it's that "the group was relatively unsophisticated, penetrated early and not connected to any outside group."

One Newburgh resident who lived near Payen described the 21-year-old parolee as a "strange kid."

“He had a lot of psychological problems," Hamin Rashada told the Times Herald-Record.

Since serving a 15-month prison term, Payen lived alternatively in Newburgh and Middletown in upstate New York, with occasional stints on the street.

Rashada told the paper he met Payen through the Orange County Transition Center, a program that helps re-integrate parolees back into society.

A senior life coach with the program, Rashada worked with Payen and encouraged him to attend Friday prayers at Masjid al-Ikhlas in Newburgh, where Rashada is an assistant imam, according to the Herald-Record.

But Payen only attended the Newburgh mosque occasionally, Rashada told the paper. He said he assumed the former inmate must have been introduced to Islam in prison, where misunderstandings of its philosophies can occur because educated teachers can be difficult to find.

When he did attend, Rashada said Payen would try to impress other members of the mosque with knowledge of Islam, but was often incorrect.

Payen would then become quiet and wander off, Rashada told the paper.

A Jewish human rights group issued a statement saying the alleged plot and arrests show that Jews in the United States aren't safe.

"The shocking plan to blow up a Jewish house of prayer with what the jihadist terrorists thought were C-4 explosives is dramatic proof that the dangers from such fanaticism have not passed and that American Jews must maintain their vigilance," the Simon Wiesenthal Center said.